1. Field of the Invention
The present invention relates to agricultural implements, and, more particularly, to a system that rephases series hydraulic cylinders of an agricultural implement.
2. Description of the Related Art
Farmers utilize a wide variety of tillage implements to prepare soil for planting. Some such implements include two or more sections coupled together to perform multiple functions as they are pulled through fields by a tractor. For example, a field cultivator is capable of simultaneously tilling soil and leveling the tilled soil in preparation for planting. A field cultivator has a frame that carries a number of cultivator shanks with shovels at their lower ends for tilling the soil. The field cultivator converts compacted soil into a level seedbed with a consistent depth for providing excellent conditions for planting of a crop. Grass or residual crop material disposed on top of the soil is also worked into the seedbed so that it does not interfere with a seeding implement subsequently passing through the seedbed.
Tillage equipment prepares the soil by way of mechanical agitation of various types, such as digging, stirring, and overturning. Examples of which include ploughing (overturning with moldboards or chiseling with chisel shanks), rototilling, rolling with cultipackers or other rollers, harrowing, and cultivating with cultivator shanks.
The lifting of the tillage elements from the field, and the folding of the sections are typically actuated with a hydraulic system. Hydraulic systems that utilize a pressurized fluid through a series of pistons is generally known. Typically, it is important to have the pistons of a series arrangement synchronized with respect to one another. Synchronization of the system is accomplished by having the pistons reach the top and the bottom of their respective strokes at the same time. This is especially desirable when raising and lowering components of a piece of equipment.
During operation of the hydraulic system the pistons may get out of sync due to imperfections in the pistons/cylinders and due to wear of various parts on the pistons and cylinders. Most commonly, seals can wear and begin to degrade over time, thereby allowing the hydraulic fluid within the system to bypass the pistons and/or leak out of the system. When the fluid is removed from the system or becomes unbalanced, by leaking or otherwise, a decrease in pressure within the system occurs causing the pistons to travel by differing amounts or by a varying speed, thereby causing the pistons to begin and end their strokes at different times. During the raising and lowering of the components of the equipment, the variation in piston movement will not allow the components to move smoothly and safely. To remedy this problem, the pistons need to be resynced. The process of resyncing the pistons in the series hydraulic system is commonly known as rephasing.
The typical way to rephase hydraulic systems require an operator to notice the need to rephase, and the operator then causes the system to fully extend the hydraulic actuators to allow the built in fluid channels to adjust the fluid present between the pistons.
A problem with these systems is that the operation requires the operator to note the need and to execute the sequence.
What is needed in the art is a system that will detect the need for rephrasing and select a time that is energy efficient and not when the implement is performing its primary duty.